This application claims the priority of German patent document 10 2008 024 134.2-55, filed May 19, 2008, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a method and apparatus for wireless transmission of an electrically complex signal, in which the length of the transmission route is measured, for the purpose of correcting the phase response to changes in the length of the transmission route.
This method is of importance, for example, in the complex characterization of large electromagnetic fields, particularly for antenna near-field measurements. As a result, for example, floating or flying moving platforms could be used to position antenna measuring heads, for which line transmission of complex signals (for example, measuring or reference signals) would not be possible or could be implemented only at a high risk or with high expenditures.
In the state of the art, line transmission of signals has been used to transmit the complex characterization of electromagnetic fields, particularly for high-frequency or antenna near-field measurements. However, such line transmission is limited to stationary measuring systems of limited size, because of limited lengths when arranging moving and phase-sensitive high-frequency lines.
One problem that occurs in a wireless transmission of measuring signals is the phase shift which occurs as a result of the continuous length change of the wireless transmission route between a flying platform and the ground station. Such phase shift does not occur in line transmission because of the constant line length (or it occurs only to a minor extent, due to elongation or twisting of the line).
It therefore is an object of the present invention to provide a method and apparatus which permit wireless transmission of a complex signal, which make it possible to correct the phase response that is caused by the length of the transmission route.
This and other objects and advantages are achieved by the method and apparatus according to the present invention, which includes a provision for measuring the length of a transmission route to a moving platform, as well as for transmitting complex measuring or reference signals. Components of a device for transmitting complex measuring or reference signals are arranged beside components of a device for measuring the length of the transmission route to the moving platform, so that the changes of the length of the transmission route are the same for both devices.
According to a further feature of the invention, the components for measuring the length of the transmission route and the components for transmitting complex measuring signals or reference signals are mounted on a common motional axis. Moreover, one of the devices may be a stationary ground-side device or a moving device, and the platform is a moving platform. Alternatively, the platform itself may be a stationary device.
The invention also includes a method for wireless transmission of phase critical signals for a system, such as described above, in which measurement of the length of the transmission route occurs isochronously.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.